Langerhans cells express matrix metalloproteinases 9 and 2 and tissue inhibitors of metalloproteinases 1 and 2 in healthy human gingival tissue and in periodontitis.

Background: As antigen-presenting cells, Langerhans cells may play an important role in the initiation and maintenance of periodontal disease. This study is the first report that extends our knowledge of the expression of matrix metalloproteinases and their endogenous tissue inhibitors by Langerhans cells in healthy and diseased gingival tissues.
Methods: Single and double immunolabeling procedures were carried out using monoclonal antibodies against CD1a, matrix metalloproteinases 2 and 9, and tissue inhibitors of matrix metalloproteinases 1 and 2, and analyzed by conventional and confocal microscopes.
Results: Langerhans cells expressed matrix metalloproteinases 2 and 9, and tissue inhibitors of matrix metalloproteinases 1 and 2 in healthy and diseased gingival tissues. The tissue inhibitors of matrix metalloproteinase-positive Langerhans cells were mainly observed in the upper epithelial layers. Matrix metalloproteinase 9-positive Langerhans cells were observed especially during periodontitis and in the basal epithelial layer or crossing the basement membrane.
Conclusion: During periodontal disease, changes in the expression of matrix metalloproteinases and their tissue inhibitors by gingival Langerhans cells could be implicated in the migration of the cells towards the connective tissue.